Respiratory depression or “labored breathing” is frequently seen in patients with various kinds of diseases. Oxygen is usually provided to patients either through noses or mouths to improve the oxygenation and correct hypoxia. However, in patients with severe respiration depression or apnea, simple inhalation of oxygen via the nose or mouth may not be adequate or impossible and result in hypoxia and/or hypercapnia. Tracheal intubation and mechanical ventilation can help patient's breath.
However, tracheal intubation is invasive and may have multiple complications related to tracheal intubation (e.g. requirement of significant level of sedation, airway damage, failed intubation in a difficult airway and troubles to wean from the ventilators).
Heavy sedations with intravenous infusion of general anesthetic propofol are frequently used to assist outpatient procedures (e.g. endoscope examinations of gastrointestinal tracts or bile ducts, bronchoscope etc.). Propofol sedation can depress patient's breathing severely especially when patient is on prone position. Inhalation of oxygen via nose or mouth with patient's natural breathing is often not adequate to correct hypoxia and/or hypercapnia.
Mask ventilation is often impossible because of the endoscope in the mouth. Tracheal intubations and mechanical ventilation are usually not chosen because these procedures are often short and do not warrant full general anesthesia.
Hypoxia during tracheal intubation is the most common complication causing morbidity and mortality in the clinical practice of anesthesia, which is often related to an unexpected difficult airway. Occasionally, both mask ventilation and tracheal intubation are impossible in an apnea patient resulting in non-ventilation and non-intubation airway emergency. Lack of an effective airway device that maintains oxygenation and ventilation during the process of tracheal intubation in an apnea patient contribute to the morbidity and mortality. It is lifesaving if oxygen can be provided to a patient and adequate oxygen levels maintained at this time.